The level of fat included in diets is of concern in many channels, particularly with respect to meat products or foods which contain animal-originating meat components. Meat food products are available which fall into the generally low-fat category. In the past, it has been considered to be satisfactory if the fat content of an uncooked raw meat supply is within a general magnitude on the order of about 10 weight percent or even 5 weight percent. While fat percentages of this general magnitude for raw meat materials represent a substantial step toward reducing the intake of fat for those who consume products made from this reduced-fat raw material, it would be beneficial to provide a highly functional fat-reduced meat raw material having a much lower fat content.
Awareness of fat intake has led consumers to value highly those food sources which are relatively low in fat or have virtually no fat content. Traditionally, many meat products have been perceived by certain groups as being products that are relatively high in fat content. Various techniques have made available meat products having fat percentages of 5% or less, such as at the 1% to 4% by weight level of fat in the meat product. Examples are turkey breast products which can achieve fat levels at the lower values of these ranges.
Consumer perception has developed along these lines to the extent that there is a desire to have even these relatively low fat percentages reduced further, ideally to arrive at a fat-free condition or a nominally fat-free condition. For example, current guidelines which are followed by the USDA permit many packaged meat products to be labeled as "fat-free" provided the amount of fat in the packaged meat product is less than 0.5 gram of fat per nutritional "references amount" of grams per serving of the meat product. This translates to a weight percent which can vary depending upon the particular meat products. For example, for a sliced meat or sausage product, the reference amount is 55 grams, and the amount of fat allowable in this type of fat-free product is less than 0.91% by weight of the total packaged meat product. Such a product is thus properly designated as "free" of fat, and nutritional labelling properly specifies a zero ("0") as the reported fat content.
Accordingly, there is an important need for meat products having a fat content which meets these zero, or nominal zero levels. Recently, different approaches have been used or proposed which are capable of providing raw lean meat supplies which have fat values low enough to be incorporated into the production of products which meet these fat-free criteria.
One type of approach in this regard involves grinding and centrifuging to provide a flow of reduced-fat meat without substantial denaturation thereof. Included are the approaches of Roehrig et al. U.S. Pat. No. 5,382,444, of U.S. patent application Ser. No. 08/694,146, filed Aug. 8, 1996, and of their related applications, incorporated hereinto by reference.
Another approach for providing raw lean muscle supplies processes whole muscle sections so as to provide a flow of muscle core meat cuts of especially lean attributes. This procedure includes separating the raw muscle supplies along cut lines to collect the most desirable naturally occurring muscles. This trimming type of approach is described in U.S. patent application Ser. No. 08/510,993, filed Aug. 3, 1995, incorporated hereinto by reference.
A further approach incorporates sinew removal in its fat reduction approach. It is described in U.S. patent application Ser. No. 08/740,135, filed Oct. 22, 1996, incorporated hereinto by reference. This approach recognizes that many fat removal or dilution procedures fail to remove sinew from the meat and therefore fail to address disadvantages attendant to the presence of sinew, including toughness, chewiness, and/or the presence of fat cells associated with or attached to sinew. As used herein, the term sinew refers to gristle and other connective tissues which are naturally incorporated with muscle tissue. This sinew is generally intimately interwoven with the muscle tissue. Fatty deposits are associated with and attached to the intimately interspersed sinew, which is typically not susceptible to removal by hand trimming, for example. This approach recognizes that the removal of a significant and substantial portion of sinew without grinding the meat is an important objective.
Even with these approaches for providing supplies of raw lean meat, it is still important to check that the meat supplies have fat percentages as low as required in order to be certain that the fat-free meats being produced always adhere to the governmental definition. However sophisticated these processes are, it is still the case that meat processing is subject to numerous sources of variation, not found in other industries, making the problem of product consistency quite difficult. Raw meat trimmings are sold to meat processors based upon the fat content, and incoming lots are routinely analyzed by the meat processor to check for the supplier's contractual compliance. Thus, the raw material input to any of these processes can vary, leaving open the possibility of at least a portion of that variation affecting the output from the particular process used in preparing raw lean meat for fat free production. Accordingly, there is a need for ongoing monitoring of fat content of these raw lean meat supplies. One possible option could be chemical analysis of sampled lots for moisture, fat and protein. Such chemical analysis testing is an invasive testing procedure that can be time consuming and inefficient and cannot test an entire meat flow.
In contrast, testing may be performed in a noninvasive manner through the use of microwave sensors. These provide a valuable improvement in monitoring meat flows. However, heretofore microwave sensors have not been required to monitor very low-fat raw lean meat supplies. It has been discovered that such microwave sensor equipment typically is not adequate to consistently monitor these very low-fat meat supplies. More particularly, it has been discovered that the sensitivity of this equipment to temperature variations renders it unreliable for a very low fat application.
The present invention addresses this problem by providing an inventive method and apparatus for calibrating microwave sensors for measurement of meat fat, protein, and moisture content and further separating portions of the meat that exceed the standard fat, protein, and moisture content. Temperature calibrating according to the invention alleviates a persistent erroneous measurement problem which developed in attempting to use available equipment for measuring very low levels of meat parameters.